The invention pertains generally to fluoro-substitution of unsaturated compounds and in particular to double fluorosubstitution of acetylene compounds.
The substitution of hydrogen by fluorine in organic molecules influences various properties and stabilize many molecular structures. Improvement of oxidative, thermal, and hydrolytic properties of such partially or totally fluorniated materials is well documented.
Fluorination of highly reactive unsaturated compounds, e.g. acetylenes, is very difficult to control. Acetylenic and diacetylenic compounds polymerize spontaneously at room temperature and below, and as a result, stabilized monomer compounds of such fluorinated derivatives are not readily attainable in yields considered to be practical.
No direct methods to prepare mono- or di-substituted derivates are known. Indirect methods involving multi-step coupling reactions of the acetylenic fragments have been used to prepare symmetrical derivates of diacetylene. Examples of fluorinated diacetylene prepared in this manner are disclosed in Norris, W. P. and Finnegan, W. G. J. Org. Chem. 1966, 31, 3292 and Bruce M. I. and Cullen, W. R. Fluorine Chemistry Reviews 1969, 4, 79. Those methods have many steps and yield mixtures of coupled products.